Re: If you want privacy...
Well, I created my new account a couple of years ago, and only started occasionally using it in the last few months - and I don't have a mobile set, so if they do insist it's very recent.
(I don't log-in often because, frankly, it's even more crap now than it used to be many years ago. So much so that despite saying around Christmas that I'd start using it again, I really can't be arsed - so I'm not bothering to look for and add friends; if anyone who knows me spots me on there, and they send a request, I'll probably accept it - but it's not happening the other way around. As a result, I have just three or four friends on there!)
I have spotted something odd, though - or perhaps creepy would be a better word. In fact, yes, I think creepy is a much better word, especially if preceded by "extremely fucking"
If I go into my ad settings on Facebook, under "Your interests" it lists Plex.
I did install Plex in three places, and removed it again - prior to my new, limited use of Facebook. But I haven't "Liked" Plex on Facebook. I haven't even mentioned Plex on Facebook. There should be no way Facebook can know that I ever tried it - yet there it is.
(I do have suspicions about how it got there, but nothing concrete. I need to look into it a little more and write it up at some point.)